How to map an Java object to clob in H2 and to json in Postgres using Hibernate

Question

I have some trouble mapping my java Objects to JSON columns in progress whil I want H2 to store it as clob (since there is no json type)

I use Hibernate with ddl-auto and want it to create the correct column types. In addition Spring-data-rest should be able to map the objects.

For sprint data rest it would be best to use a @Converter , therefor I can't use @Type / UserTypes for hibernate.

I have a working solution with a UserType and 2 custom dialects (one for Postgres and one for H2). But I can't solve the problem with using converters. It seems Hibernate only knows the converted type, which is String and generates varchar columns. But I can't map all Strings to JSON for Postgres ...

I'm a bit stuck here. So I would be happy for any hints that I can try out.

Answer 1

import javax.annotation.Nonnull
import javax.persistence.*

@Entity
class AdhocDocument {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    Long id

    String lookupKey // use a guid here
    String loggingKey // use a guid here

    @Lob
    @Column(name = "payload", columnDefinition="BLOB")
    private byte[] payload

    String toString() { "[${lookupKey}, ${loggingKey} ]"}
}